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* net: skb->dst accessorsEric Dumazet2009-06-03
| | | | | | | | | | | | | | | | | | Define three accessors to get/set dst attached to a skb struct dst_entry *skb_dst(const struct sk_buff *skb) void skb_dst_set(struct sk_buff *skb, struct dst_entry *dst) void skb_dst_drop(struct sk_buff *skb) This one should replace occurrences of : dst_release(skb->dst) skb->dst = NULL; Delete skb->dst field Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: extend ECN sysctl to allow server-side only ECNIlpo Järvinen2009-05-04
| | | | | | | | | | | | | | | | | | | | | | | | | | This should be very safe compared with full enabled, so I see no reason why it shouldn't be done right away. As ECN can only be negotiated if the SYN sending party is also supporting it, somebody in the loop probably knows what he/she is doing. If SYN does not ask for ECN, the server side SYN-ACK is identical to what it is without ECN. Thus it's quite safe. The chosen value is safe w.r.t to existing configs which choose to currently set manually either 0 or 1 but silently upgrades those who have not explicitly requested ECN off. Whether to just enable both sides comes up time to time but unless that gets done now we can at least make the servers aware of ECN already. As there are some known problems to occur if ECN is enabled, it's currently questionable whether there's any real gain from enabling clients as servers mostly won't support it anyway (so we'd hit just the negative sides). After enabling the servers and getting that deployed, the client end enable really has some potential gain too. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: fix mid-wq adjustment helperIlpo Järvinen2009-04-20
| | | | | | | | | | Just noticed while doing some new work that the recent mid-wq adjustment logic will misbehave when FACK is not in use (happens either due sysctl'ed off or auto-detected reordering) because I forgot the relevant TCPCB tagbit. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: miscounts due to tcp_fragment pcount resetIlpo Järvinen2009-04-02
| | | | | | | | | | | | | | | | | It seems that trivial reset of pcount to one was not sufficient in tcp_retransmit_skb. Multiple counters experience a positive miscount when skb's pcount gets lowered without the necessary adjustments (depending on skb's sacked bits which exactly), at worst a packets_out miscount can crash at RTO if the write queue is empty! Triggering this requires mss change, so bidir tcp or mtu probe or like. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de> Tested-by: Uwe Bugla <uwe.bugla@gmx.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: add helper for counter tweaking due mid-wq changeIlpo Järvinen2009-04-02
| | | | | | | | | We need full-scale adjustment to fix a TCP miscount in the next patch, so just move it into a helper and call for that from the other places. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: simplify tcp_current_mssIlpo Järvinen2009-03-15
| | | | | | | | | | | | | | | | | | | | There's very little need for most of the callsites to get tp->xmit_goal_size updated. That will cost us divide as is, so slice the function in two. Also, the only users of the tp->xmit_goal_size are directly behind tcp_current_mss(), so there's no need to store that variable into tcp_sock at all! The drop of xmit_goal_size currently leaves 16-bit hole and some reorganization would again be necessary to change that (but I'm aiming to fill that hole with u16 xmit_goal_size_segs to cache the results of the remaining divide to get that tso on regression). Bring xmit_goal_size parts into tcp.c Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Cc: Evgeniy Polyakov <zbr@ioremap.net> Cc: Ingo Molnar <mingo@elte.hu> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: remove pointless .dsack/.num_sacks codeIlpo Järvinen2009-03-15
| | | | | | | | | | | | | | | | | | | | | | | In the pure assignment case, the earlier zeroing is still in effect. David S. Miller raised concerns if the ifs are there to avoid dirtying cachelines. I came to these conclusions: > We'll be dirty it anyway (now that I check), the first "real" statement > in tcp_rcv_established is: > > tp->rx_opt.saw_tstamp = 0; > > ...that'll land on the same dword. :-/ > > I suppose the blocks are there just because they had more complexity > inside when they had to calculate the eff_sacks too (maybe it would > have been better to just remove them in that drop-patch so you would > have had less head-ache :-)). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: tcp_init_wl / tcp_update_wl argument cleanupHantzis Fotis2009-03-03
| | | | | | | | | | | The above functions from include/net/tcp.h have been defined with an argument that they never use. The argument is 'u32 ack' which is never used inside the function body, and thus it can be removed. The rest of the patch involves the necessary changes to the function callers of the above two functions. Signed-off-by: Hantzis Fotis <xantzis@ceid.upatras.gr> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: get rid of two unnecessary u16s in TCP skb flags copyingIlpo Järvinen2009-03-02
| | | | | | | | | | | | | I guess these fields were one day 16-bit in the struct but nowadays they're just using 8 bits anyway. This is just a precaution, didn't result any change in my case but who knows what all those varying gcc versions & options do. I've been told that 16-bit is not so nice with some cpus. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: kill eff_sacks "cache", the sole user can calculate itselfIlpo Järvinen2009-03-02
| | | | | | | | Also fixes insignificant bug that would cause sending of stale SACK block (would occur in some corner cases). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: drop unnecessary local var in collapseIlpo Järvinen2009-03-02
| | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: fix corner case issue in segmentation during rexmittingIlpo Järvinen2009-03-02
| | | | | | | | | | | If cur_mss grew very recently so that the previously G/TSOed skb now fits well into a single segment it would get send up in parts unless we calculate # of segments again. This corner-case could happen eg. after mtu probe completes or less than previously sack blocks are required for the opposite direction. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Don't clear hints when tcp_fragmentingIlpo Järvinen2009-03-02
| | | | | | | | | | | | | 1) We didn't remove any skbs, so no need to handle stale refs. 2) scoreboard_skb_hint is trivial, no timestamps were changed so no need to clear that one 3) lost_skb_hint needs tweaking similar to that of tcp_sacktag_one(). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: deferring in middle of queue makes very little senseIlpo Järvinen2009-03-02
| | | | | | | | | If skb can be sent right away, we certainly should do that if it's in the middle of the queue because it won't get more data into it. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: don't backtrack to sacked skbsIlpo Järvinen2009-03-02
| | | | | | | | | | | | | Backtracking to sacked skbs is a horrible performance killer since the hint cannot be advanced successfully past them... ...And it's totally unnecessary too. In theory this is 2.6.27..28 regression but I doubt anybody can make .28 to have worse performance because of other TCP improvements. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge branch 'master' of /home/davem/src/GIT/linux-2.6/David S. Miller2009-02-24
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| * tcp: remove obsoleted comment about different passesIlpo Järvinen2009-02-18
| | | | | | | | | | | | | | This is obsolete since the passes got combined. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* | tcp: Always set urgent pointer if it's beyond snd_nxtHerbert Xu2009-02-22
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Our TCP stack does not set the urgent flag if the urgent pointer does not fit in 16 bits, i.e., if it is more than 64K from the sequence number of a packet. This behaviour is different from the BSDs, and clearly contradicts the purpose of urgent mode, which is to send the notification (though not necessarily the associated data) as soon as possible. Our current behaviour may in fact delay the urgent notification indefinitely if the receiver window does not open up. Simply matching BSD however may break legacy applications which incorrectly rely on the out-of-band delivery of urgent data, and conversely the in-band delivery of non-urgent data. Alexey Kuznetsov suggested a safe solution of following BSD only if the urgent pointer itself has not yet been transmitted. This way we guarantee that when the remote end sees the packet with non-urgent data marked as urgent due to wrap-around we would have advanced the urgent pointer beyond, either to the actual urgent data or to an as-yet untransmitted packet. The only potential downside is that applications on the remote end may see multiple SIGURG notifications. However, this would occur anyway with other TCP stacks. More importantly, the outcome of such a duplicate notification is likely to be harmless since the signal itself does not carry any information other than the fact that we're in urgent mode. Thanks to Ilpo Järvinen for fixing a critical bug in this and Jeff Chua for reporting that bug. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* Revert "tcp: Always set urgent pointer if it's beyond snd_nxt"David S. Miller2009-02-05
| | | | | | | | This reverts commit 64ff3b938ec6782e6585a83d5459b98b0c3f6eb8. Jeff Chua reports that it breaks rlogin for him. Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Always set urgent pointer if it's beyond snd_nxtHerbert Xu2008-12-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Our TCP stack does not set the urgent flag if the urgent pointer does not fit in 16 bits, i.e., if it is more than 64K from the sequence number of a packet. This behaviour is different from the BSDs, and clearly contradicts the purpose of urgent mode, which is to send the notification (though not necessarily the associated data) as soon as possible. Our current behaviour may in fact delay the urgent notification indefinitely if the receiver window does not open up. Simply matching BSD however may break legacy applications which incorrectly rely on the out-of-band delivery of urgent data, and conversely the in-band delivery of non-urgent data. Alexey Kuznetsov suggested a safe solution of following BSD only if the urgent pointer itself has not yet been transmitted. This way we guarantee that when the remote end sees the packet with non-urgent data marked as urgent due to wrap-around we would have advanced the urgent pointer beyond, either to the actual urgent data or to an as-yet untransmitted packet. The only potential downside is that applications on the remote end may see multiple SIGURG notifications. However, this would occur anyway with other TCP stacks. More importantly, the outcome of such a duplicate notification is likely to be harmless since the signal itself does not carry any information other than the fact that we're in urgent mode. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: fix tso_should_defer in 64bitIlpo Järvinen2008-12-06
| | | | | | | | | | | | | | Since jiffies is unsigned long, the types get expanded into that and after long enough time the difference will therefore always be > 1 (and that probably happens near boot as well as iirc the first jiffies wrap is scheduler close after boot to find out problems related to that early). This was originally noted by Bill Fink in Dec'07 but nobody never ended fixing it. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: use tcp_write_xmit also in tcp_push_oneIlpo Järvinen2008-12-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | tcp_minshall_update is not significant difference since it only checks for not full-sized skb which is BUG'ed on the push_one path anyway. tcp_snd_test is tcp_nagle_test+tcp_cwnd_test+tcp_snd_wnd_test, just the order changed slightly. net/ipv4/tcp_output.c: tcp_snd_test | -89 tcp_mss_split_point | -91 tcp_may_send_now | +53 tcp_cwnd_validate | -98 tso_fragment | -239 __tcp_push_pending_frames | -1340 tcp_push_one | -146 7 functions changed, 53 bytes added, 2003 bytes removed, diff: -1950 net/ipv4/tcp_output.c: tcp_write_xmit | +1772 1 function changed, 1772 bytes added, diff: +1772 tcp_output.o.new: 8 functions changed, 1825 bytes added, 2003 bytes removed, diff: -178 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* Merge branch 'master' of ↵David S. Miller2008-12-06
|\ | | | | | | | | | | | | | | | | master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/wireless/iwlwifi/iwl-core.c drivers/net/wireless/iwlwifi/iwl-sta.c
| * tcp: make urg+gso work for real this timeIlpo Järvinen2008-12-04
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I should have noticed this earlier... :-) The previous solution to URG+GSO/TSO will cause SACK block tcp_fragment to do zig-zig patterns, or even worse, a steep downward slope into packet counting because each skb pcount would be truncated to pcount of 2 and then the following fragments of the later portion would restore the window again. Basically this reverts "tcp: Do not use TSO/GSO when there is urgent data" (33cf71cee1). It also removes some unnecessary code from tcp_current_mss that didn't work as intented either (could be that something was changed down the road, or it might have been broken since the dawn of time) because it only works once urg is already written while this bug shows up starting from ~64k before the urg point. The retransmissions already are split to mss sized chunks, so only new data sending paths need splitting in case they have a segment otherwise suitable for gso/tso. The actually check can be improved to be more narrow but since this is late -rc already, I'll postpone thinking the more fine-grained things. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* | tcp: move some parts from tcp_write_xmitIlpo Järvinen2008-12-06
| | | | | | | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* | Merge branch 'master' of ↵David S. Miller2008-11-27
|\| | | | | | | | | | | | | | | | | | | | | master.kernel.org:/pub/scm/linux/kernel/git/davem/net-2.6 Conflicts: drivers/net/hp-plus.c drivers/net/wireless/ath5k/base.c drivers/net/wireless/ath9k/recv.c net/wireless/reg.c
| * tcp: Do not use TSO/GSO when there is urgent dataPetr Tesarik2008-11-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch fixes http://bugzilla.kernel.org/show_bug.cgi?id=12014 Since most (if not all) implementations of TSO and even the in-kernel software GSO do not update the urgent pointer when splitting a large segment, it is necessary to turn off TSO/GSO for all outgoing traffic with the URG pointer set. Looking at tcp_current_mss (and the preceding comment) I even think this was the original intention. However, this approach is insufficient, because TSO/GSO is turned off only for newly created frames, not for frames which were already pending at the arrival of a message with MSG_OOB set. These frames were created when TSO/GSO was enabled, so they may be large, and they will have the urgent pointer set in tcp_transmit_skb(). With this patch, such large packets will be fragmented again before going to the transmit routine. As a side note, at least the following NICs are known to screw up the urgent pointer in the TCP header when doing TSO: Intel 82566MM (PCI ID 8086:1049) Intel 82566DC (PCI ID 8086:104b) Intel 82541GI (PCI ID 8086:1076) Broadcom NetXtreme II BCM5708 (PCI ID 14e4:164c) Signed-off-by: Petr Tesarik <ptesarik@suse.cz> Signed-off-by: David S. Miller <davem@davemloft.net>
* | tcp: move tcp_simple_retransmit to tcp_inputIlpo Järvinen2008-11-25
| | | | | | | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* | tcp: collapse more than two on retransmissionIlpo Järvinen2008-11-25
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I always had thought that collapsing up to two at a time was intentional decision to avoid excessive processing if 1 byte sized skbs are to be combined for a full mtu, and consecutive retransmissions would make the size of the retransmittee double each round anyway, but some recent discussion made me to understand that was not the case. Thus make collapse work more and wait less. It would be possible to take advantage of the shifting machinery (added in the later patch) in the case of paged data but that can be implemented on top of this change. tcp_skb_is_last check is now provided by the loop. I tested a bit (ss-after-idle-off, fill 4096x4096B xfer, 10s sleep + 4096 x 1byte writes while dropping them for some a while with netem): . 16774097:16775545(1448) ack 1 win 46 . 16775545:16776993(1448) ack 1 win 46 . ack 16759617 win 2399 P 16776993:16777217(224) ack 1 win 46 . ack 16762513 win 2399 . ack 16765409 win 2399 . ack 16768305 win 2399 . ack 16771201 win 2399 . ack 16774097 win 2399 . ack 16776993 win 2399 . ack 16777217 win 2399 P 16777217:16777257(40) ack 1 win 46 . ack 16777257 win 2399 P 16777257:16778705(1448) ack 1 win 46 P 16778705:16780153(1448) ack 1 win 46 FP 16780153:16781313(1160) ack 1 win 46 . ack 16778705 win 2399 . ack 16780153 win 2399 F 1:1(0) ack 16781314 win 2399 While without drop-all period I get this: . 16773585:16775033(1448) ack 1 win 46 . ack 16764897 win 9367 . ack 16767793 win 9367 . ack 16770689 win 9367 . ack 16773585 win 9367 . 16775033:16776481(1448) ack 1 win 46 P 16776481:16777217(736) ack 1 win 46 . ack 16776481 win 9367 . ack 16777217 win 9367 P 16777217:16777218(1) ack 1 win 46 P 16777218:16777219(1) ack 1 win 46 P 16777219:16777220(1) ack 1 win 46 ... P 16777247:16777248(1) ack 1 win 46 . ack 16777218 win 9367 . ack 16777219 win 9367 ... . ack 16777233 win 9367 . ack 16777248 win 9367 P 16777248:16778696(1448) ack 1 win 46 P 16778696:16780144(1448) ack 1 win 46 FP 16780144:16781313(1169) ack 1 win 46 . ack 16780144 win 9367 F 1:1(0) ack 16781314 win 9367 The window seems to be 30-40 segments, which were successfully combined into: P 16777217:16777257(40) ack 1 win 46 Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* | net: clean up net/ipv4/ip_sockglue.c tcp_output.cJianjun Kong2008-11-03
|/ | | | | Signed-off-by: Jianjun Kong <jianjun@zeuux.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* syncookies: fix inclusion of tcp options in syn-ackFlorian Westphal2008-10-27
| | | | | | | | | | | | | David Miller noticed that commit 33ad798c924b4a1afad3593f2796d465040aadd5 '(tcp: options clean up') did not move the req->cookie_ts check. This essentially disabled commit 4dfc2817025965a2fc78a18c50f540736a6b5c24 '[Syncookies]: Add support for TCP options via timestamps.'. This restores the original logic. Signed-off-by: Florian Westphal <fw@strlen.de> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Restore ordering of TCP options for the sake of inter-operabilityIlpo Järvinen2008-10-23
| | | | | | | | | | | | | | | | | | | | | | | | | This is not our bug! Sadly some devices cannot cope with the change of TCP option ordering which was a result of the recent rewrite of the option code (not that there was some particular reason steming from the rewrite for the reordering) though any ordering of TCP options is perfectly legal. Thus we restore the original ordering to allow interoperability with/through such broken devices and add some warning about this trap. Since the reordering just happened without any particular reason, this change shouldn't cost us anything. There are already couple of known failure reports (within close proximity of the last release), so the problem might be more wide-spread than a single device. And other reports which may be due to the same problem though the symptoms were less obvious. Analysis of one of the case revealed (with very high probability) that sack capability cannot be negotiated as the first option (SYN never got a response). Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Reported-by: Aldo Maggi <sentiniate@tiscali.it> Tested-by: Aldo Maggi <sentiniate@tiscali.it> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: should use number of sack blocks instead of -1Ilpo Järvinen2008-10-21
| | | | | | | | | | | | | | | | | | While looking for the recent "sack issue" I also read all eff_sacks usage that was played around by some relevant commit. I found out that there's another thing that is asking for a fix (unrelated to the "sack issue" though). This feature has probably very little significance in practice. Opposite direction timeout with bidirectional tcp comes to me as the most likely scenario though there might be other cases as well related to non-data segments we send (e.g., response to the opposite direction segment). Also some ACK losses or option space wasted for other purposes is necessary to prevent the earlier SACK feedback getting to the sender. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: kill pointless urg_modeIlpo Järvinen2008-10-07
| | | | | | | | | | | | | | | | | | | | | | It all started from me noticing that this urgent check in tcp_clean_rtx_queue is unnecessarily inside the loop. Then I took a longer look to it and found out that the users of urg_mode can trivially do without, well almost, there was one gotcha. Bonus: those funny people who use urg with >= 2^31 write_seq - snd_una could now rejoice too (that's the only purpose for the between being there, otherwise a simple compare would have done the thing). Not that I assume that the rest of the tcp code happily lives with such mind-boggling numbers :-). Alas, it turned out to be impossible to set wmem to such numbers anyway, yes I really tried a big sendfile after setting some wmem but nothing happened :-). ...Tcp_wmem is int and so is sk_sndbuf... So I hacked a bit variable to long and found out that it seems to work... :-) Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Port redirection support for TCPKOVACS Krisztian2008-10-01
| | | | | | | | | | | | | | | Current TCP code relies on the local port of the listening socket being the same as the destination address of the incoming connection. Port redirection used by many transparent proxying techniques obviously breaks this, so we have to store the original destination port address. This patch extends struct inet_request_sock and stores the incoming destination port value there. It also modifies the handshake code to use that value as the source port when sending reply packets. Signed-off-by: KOVACS Krisztian <hidden@sch.bme.hu> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Fix order of tests in tcp_retransmit_skb()David S. Miller2008-09-23
| | | | | | | tcp_write_queue_next() must only be made if we know that tcp_skb_is_last() evaluates to false. Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: advertise MSS requested by userTom Quetchenbach2008-09-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | I'm trying to use the TCP_MAXSEG option to setsockopt() to set the MSS for both sides of a bidirectional connection. man tcp says: "If this option is set before connection establishment, it also changes the MSS value announced to the other end in the initial packet." However, the kernel only uses the MTU/route cache to set the advertised MSS. That means if I set the MSS to, say, 500 before calling connect(), I will send at most 500-byte packets, but I will still receive 1500-byte packets in reply. This is a bug, either in the kernel or the documentation. This patch (applies to latest net-2.6) reduces the advertised value to that requested by the user as long as setsockopt() is called before connect() or accept(). This seems like the behavior that one would expect as well as that which is documented. I've tried to make sure that things that depend on the advertised MSS are set correctly. Signed-off-by: Tom Quetchenbach <virtualphtn@gmail.com> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: back retransmit_high when it over-estimatedIlpo Järvinen2008-09-21
| | | | | | | | | | | If lost skb is sacked, we might have nothing to retransmit as high as the retransmit_high is pointing to, so place it lower to avoid unnecessary walking. This is mainly for the case where high L'ed skbs gets sacked. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: don't clear retransmit_skb_hint when not necessaryIlpo Järvinen2008-09-21
| | | | | | | | | Most importantly avoid doing it with cumulative ACK. Not clearing means that we no longer need n^2 processing in resolution of each fast recovery. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: remove retransmit_skb_hint clearing from failureIlpo Järvinen2008-09-21
| | | | | | | | | This doesn't much sense here afaict, probably never has. Since fragmenting and collapsing deal the hints by themselves, there should be very little reason for the rexmit loop to do that. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: reorganize retransmit code loopsIlpo Järvinen2008-09-21
| | | | | | | | | Both loops are quite similar, so they can be combined with little effort. As a result, forward_skb_hint becomes obsolete as well. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: remove tp->lost_out guard to make joining diff nicerIlpo Järvinen2008-09-21
| | | | | | | | | | | The validity of the retransmit_high must then be ensured if no L'ed skb exits! This makes a minor change to behavior, we now have to iterate the head to find out that the loop terminates. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Reorganize skb tagbit checksIlpo Järvinen2008-09-21
| | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: remove obsolete validity concernIlpo Järvinen2008-09-21
| | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: add tcp_can_forward_retransmitIlpo Järvinen2008-09-21
| | | | | Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: convert retransmit_cnt_hint to seqnoIlpo Järvinen2008-09-21
| | | | | | | | | | | | | | | | | | | | | Main benefit in this is that we can then freely point the retransmit_skb_hint to anywhere we want to because there's no longer need to know what would be the count changes involve, and since this is really used only as a terminator, unnecessary work is one time walk at most, and if some retransmissions are necessary after that point later on, the walk is not full waste of time anyway. Since retransmit_high must be kept valid, all lost markers must ensure that. Now I also have learned how those "holes" in the rexmittable skbs can appear, mtu probe does them. So I removed the misleading comment as well. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Partial hint clearing has again become meaninglessIlpo Järvinen2008-09-21
| | | | | | | | | Ie., the difference between partial and all clearing doesn't exists anymore since the SACK optimizations got dropped by an sacktag rewrite. Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@helsinki.fi> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: fix tcp header size miscalculation when window scale is unusedPhilip Love2008-08-27
| | | | | | | | | | The size of the TCP header is miscalculated when the window scale ends up being 0. Additionally, this can be induced by sending a SYN to a passive open port with a window scale option with value 0. Signed-off-by: Philip Love <love_phil@emc.com> Signed-off-by: Adam Langley <agl@imperialviolet.org> Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: Fix bitmask test in tcp_syn_options()David S. Miller2008-07-21
| | | | | | | | | | | | | | | | | As reported by Alexey Dobriyan: CHECK net/ipv4/tcp_output.c net/ipv4/tcp_output.c:475:7: warning: dubious: !x & y And sparse is damn right! if (unlikely(!OPTION_TS & opts->options)) ^^^ size += TCPOLEN_SACKPERM_ALIGNED; OPTION_TS is (1 << 1), so condition will never trigger. Signed-off-by: David S. Miller <davem@davemloft.net>
* tcp: options clean upAdam Langley2008-07-19
| | | | | | | | | | | | | | | | | | | | | | | | | This should fix the following bugs: * Connections with MD5 signatures produce invalid packets whenever SACK options are included * MD5 signatures are counted twice in the MSS calculations Behaviour changes: * A SYN with MD5 + SACK + TS elicits a SYNACK with MD5 + SACK This is because we can't fit any SACK blocks in a packet with MD5 + TS options. There was discussion about disabling SACK rather than TS in order to fit in better with old, buggy kernels, but that was deemed to be unnecessary. * SYNs with MD5 don't include a TS option See above. Additionally, it removes a bunch of duplicated logic for calculating options, which should help avoid these sort of issues in the future. Signed-off-by: Adam Langley <agl@imperialviolet.org> Signed-off-by: David S. Miller <davem@davemloft.net>
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